The present invention relates to engine blocks and more particularly to an engine block having an oil conditioning system formed therein.
Internal combustion engines (ICEs) are commonly known in the art. Generally, ICEs operate by drawing a fuel/air mixture into a cylinder through an intake valve of a cylinder head. The fuel/air mixture is combusted in the cylinder to drive a piston downward therein. The piston is connected to a crankshaft by a connecting rod. The downward driving force of the piston rotatably drives the crankshaft for propelling a vehicle. The combusted gases within the cylinder head are driven out an exhaust valve of the cylinder head through a subsequent piston stroke.
An ICE at rest is generally at ambient temperature and, thus, all of the components, seals, lubricating oil, coolant and the like are also at ambient temperature. For proper engine operation, the lubricating oil is preferably at a temperature higher than ambient. At initial start-up, time is required to achieve a desired operational temperature for the lubricating oil by heating the lubricating oil through transferring heat generated through the combustion process. During this warm-up period, however, the ICE is operating with lubricating oil at a temperature less than the desired operational temperature, thereby adversely affecting the various components of the ICE. Additionally, traditional ICEs provide limited temperature control of the lubricating oil during operation of the ICE. Thus, it may occur that the lubricating oil achieves a temperature greater than the desired operational temperature. In order to remedy this, a separate oil cooler is sometimes implemented, thereby increasing cost, weight and required packaging envelope.
A further disadvantage of traditional ICEs is the return flow of the lubricating oil from the cylinder heads. Generally, the lubricating oil drips from the cylinder heads along exterior block wall passages, which increase packaging size and have no thermal exchange function. Such a configuration is common for overhead camshaft ICE designs. Alternatively, for push-rod valve actuation ICEs, oil flows down the interior of the engine block, often dripping directly onto the spinning crankshaft. As a result, the oil dripping onto the crankshaft is splattered within the interior of the engine block, causing the oil to foam and lose its lubricity. This can result in damage to the various bearings of the ICE.
Therefore, it is desirable in the industry to provide an oil-flow system for an ICE engine that enables quicker warm-up of the lubricating oil at start-up and regulates the oil temperature during normal ICE operation without requiring external components. The oil-flow system should also include an oil-dump passage for avoiding dripping of return oil on the crankshaft.
Accordingly, the present invention provides an internal combustion engine including a cylinder head having a first coolant flow channel formed therein and a first oil flow channel formed therein, an engine block, and an oil pan. The engine block includes a plurality of cylinders and a plurality of crank case bays, each crank case bay corresponding to at least one of the plurality of cylinders. The engine block further includes a second coolant flow channel formed adjacent to the cylinders, an oil trough formed adjacent to the second coolant flow channel and in heat transfer relationship therewith, and an oil return flow channel formed therein for providing fluid communication between the first oil flow channel of the cylinder head and the oil trough. The oil return flow channel is adjacent to the second coolant flow channel and is in heat transfer relationship therewith. The engine block further includes an oil dump flow channel formed therein for providing fluid communication from the oil trough. The oil pan is in sealed engagement with the engine block and in fluid communication with the oil dump flow channel. The oil pan collects oil, wherein the oil is pumped to the first oil flow channel of the cylinder head and flows from the cylinder head through the oil return flow channel and into the oil trough for heat transfer with coolant in the second coolant flow channel before returning to the oil pan through the oil dump flow channel.
The present invention further provides a plurality of venting channels formed within the engine block, each providing fluid communication between the plurality of crank case bays and the oil trough, wherein the venting channels enable pressurized fluid flow to the oil trough for equalizing pressure across the plurality of crank case bays. This enables bulkhead vent size to be reduced, thereby improving engine block strength.
The present invention may further include an inlet manifold in fluid communication with the cylinder head and an oil separator providing fluid communication between the oil trough and the inlet manifold for enabling pressure flow into the inlet manifold, thereby assisting crankcase ventilation to the inlet manifold. In this manner, blow-by gases, typically escaping between the cylinder walls and pistons after combustion, are relieved. Further, the separator collects oil droplets from the engine vapor and drains the collected oil back to the trough to prevent entrance into the inlet manifold, which would otherwise result in unwanted pollutants upon combustion.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.